Obesity-Health poll methodology

The Associated Press-NORC Center for Public Affairs Research Poll on obesity and diabetes was conducted from Nov. 21 to Dec. 14 by NORC at the University of Chicago. It is based on landline and cellular telephone interviews with a nationally representative random sample of 1,011 adults. Interviews included 599 respondents on landline telephones and 412 on cellular phones. No interviews were conducted Nov. 22.

Digits in the phone numbers dialed were generated randomly to reach households with unlisted and listed landline and cellphone numbers.

Interviews were conducted in English and Spanish.

As is done routinely in surveys, results were weighted or adjusted, to ensure that responses accurately reflect the populations makeup by factors such as age, sex, education and race. In addition, the weighting took into account patterns of phone use  landline only, cellphone only and both  by region.

No more than 1 time in 20 should chance variations in the sample cause the results to vary by more than plus or minus 4.2 percentage points from the answers that would be obtained if all adults in the U.S. were polled.

There are other sources of potential error in polls, including the wording and order of questions.